Objectives: Different types of patch materials are in use for aortic valve (AV) reconstruction
in children with significant AV pathology for avoidance of early valve replacement.
CardioCel (Admedus, Perth, Australia) consists of bovine pericardium treated with
the ADAPT-method (Admedus’ tissue engineering process-treated). The material has been
claimed to mitigate both the effects of inflammation and calcification locally related
to the patch material with subsequently lower rates of re-stenosis.
Methods: We studied and compared tissue reactions in CardioCel-Patch augmented AV tissue specimen.
Explants were worked up using a uniform protocol with methylmethacrylate and/or paraffin
embedding after fixation in formalin. Besides standard histology staining, Kossa stain
(for identification of calcifications) and immunohistochemical staining was applied
with antibodies specific for muscular, inflammatory, and connective tissue component
antigens. Findings regarding the aspects proliferation, calcification, and inflammation
were rated using a 4-grade scale (G0 no/G1 few/G2 moderate/G3 massive).
Results: Eight aortic valve tissue specimen (augmented with CardioCel patch material) were
examined (7 explanted surgically, 1 autopsy). Indication for explantation had been
AV stenosis in 3, AV regurgitation in 3 and suspicion for endocarditis in 1 patient.
Low-grade AV stenosis had been known in the remaining patient. Time interval between
implantation and explantation (implant time) was 8 to 29 months (mean 22 months).
Superficial endothelialization was demonstrated in all patients by immunohistochemistry.
Whereas 4 specimen showed no inflammatory cell infiltration (G1: 3; G2: 1), there
was not a single one without tissue proliferation (G1: 3, G2: 5). 6 of 8 samples with
implant times of 23 to 29 months revealed low-grade calcifications. Only the two specimens
with “short” implant times of 8 and 11 months showed no calcifications. No active
inflammation was demonstrated histologically in the patient with clinical suspicion
of endocarditis or thrombus.
Conclusion: In contrast to advertisement statements, CardioCel patches demonstrated proliferations
in every specimen and calcifications in all 6 specimen with implant times of 23 months
or more. However, histology of this patch material showed less optimal results in-short
and medium-term explants. Long-term follow-up in larger cohorts is required to determine
the definitive patch performance for AV reconstruction.
